Rubicon 4:10 to 4:88 upgrade issues (Jeep DOESNT Cares Case #79708336)

[scottryla]

LOL, having 4:88 installed in my JT Rubicon today.

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[Bbannongmu]

LOL, having 4:88 installed in my JT Rubicon today.

Nice. Good luck!

 

[Gladiator_Explr]

I had mine re-geared from 4.10 to 5.13 and have had no problems at all. I have the Tazer mini and did need to go in and change the gearing and tire size but beyond that have not head a problem. I know that there are others that have done the same but with 4.88's. I am really confused as to how you can't put 4.88's in a Dana 44 that is in a JT?

 

[Bbannongmu]

I had Mopar 4:88's installed in my Rubicon by a local Jeep dealership. Before I left the parking lot the auto start stop threw a warning light and became inoperable. I called the dealership and they assumed it was the auxiliary battery and told me I would need to bring it back and let them have it for 4 hours to test the battery and if/when it was bad they could replace it under warranty.

Fast forward a month and I drop it off to receive a call letting me know they have programmed the 4:88's but every time they start it and pull it out of the shop the auto start stop issue pops back up. When they go back into the programming it has changed back to 4:10's. They let me know I can come pick up the truck and they will work with Jeep to get new code and call me back when they get it.

Two weeks later (last Monday) I take the truck back as they now say they need to regional Jeep guy here so they can connect the system up and work with Jeep as they cant figure out what is going on. I was in the area (today Friday)so I popped in the dealership to see if they had made in progress. Here is where it gets FUN!!!

I have now been informed that you can not put 4:88's in a Rubicon because the rear diff has some air sensor in it and now that they have done both the rear and and front end both axles need to be replaced along w/ the transfer case. They informed me this is only an issue with Rubicon and that if I had a sport or Mojave no big thing. At this point I have no truck, no idea what resolution looks like and scratching my head as to how the heck this is even possible.

Please dont shoot the messenger as I am only sharing what I have been told. Please do share if you have a Rubicon, had a dealership install 4:88's and if you are not having the same problem would really appreciate a PM with your dealership name so I can have mine call yours and compare notes.

All that said I really dont want to go back to 4:10's so need to start looking at other axles as a potential resolution. Thanks in advance for any guidance, positive input or good natured go buy a Ford smack talk as it is all appropriate about right now.

@JeepCares

Calling BS on dealer on the air sensor story. Asked them to show it to you and provide the part number on the parts diagram and explain why it can’t accept proper gearing. Definitely recommend a second opinion.
The likely fix is a Tazer and relearn procedure. I’m planning to go to 4.88s soon with my manual Rubicon. I’ll be going to a gear pro. I really only let dealers do recalls and warranty work. In general, I don’t trust them. Good luck.

 

[Russler]

Update June 7th 2021. Called the dealership last night. No updates and was told this will most likely take a very long time to resolve. Still no word from @JeepCares

Thank you for all the feedback. Looking forward to getting some level of resolution.

 

[RangerG]

Update June 7th 2021. Called the dealership last night. No updates and was told this will most likely take a very long time to resolve. Still no word from @JeepCares

Thank you for all the feedback. Looking forward to getting some level of resolution.

This sounds like a computer issue. Not an axel problem.

 

[Jtschnel]

I had Mopar 4:88's installed in my Rubicon by a local Jeep dealership. Before I left the parking lot the auto start stop threw a warning light and became inoperable. I called the dealership and they assumed it was the auxiliary battery and told me I would need to bring it back and let them have it for 4 hours to test the battery and if/when it was bad they could replace it under warranty.

Fast forward a month and I drop it off to receive a call letting me know they have programmed the 4:88's but every time they start it and pull it out of the shop the auto start stop issue pops back up. When they go back into the programming it has changed back to 4:10's. They let me know I can come pick up the truck and they will work with Jeep to get new code and call me back when they get it.

Two weeks later (last Monday) I take the truck back as they now say they need to regional Jeep guy here so they can connect the system up and work with Jeep as they cant figure out what is going on. I was in the area (today Friday)so I popped in the dealership to see if they had made in progress. Here is where it gets FUN!!!

I have now been informed that you can not put 4:88's in a Rubicon because the rear diff has some air sensor in it and now that they have done both the rear and and front end both axles need to be replaced along w/ the transfer case. They informed me this is only an issue with Rubicon and that if I had a sport or Mojave no big thing. At this point I have no truck, no idea what resolution looks like and scratching my head as to how the heck this is even possible.

Please dont shoot the messenger as I am only sharing what I have been told. Please do share if you have a Rubicon, had a dealership install 4:88's and if you are not having the same problem would really appreciate a PM with your dealership name so I can have mine call yours and compare notes.

All that said I really dont want to go back to 4:10's so need to start looking at other axles as a potential resolution. Thanks in advance for any guidance, positive input or good natured go buy a Ford smack talk as it is all appropriate about right now.

@JeepCares

I have a 2020 Rubicon Gladiator and have done a number of mods. Those did include swapping out stock tires for 37’s and later changing the 4:10 gearing out for 4:88. With both of theses changes the numbers were updated in the ECM with no issues. I have a SuperChips TrailDash 2 which was used for the ECM updates.

Have highway, city, as well as trail miles on the JT since the 4:88 change. Now, on the highway the transmission bounces between 7th and 8th gears but is in 8th most of the time. Prior to the 4:88’s, very little time in 8th, generally bouncing between 6th and 7th.

The only issue we’ve had was a blown main power fuse for the CAN Bus which was inadvertently shorted when running power from the fuse box for something. In the end, decided it had nothing to do with the ECM updates.

Mopar dealer ordered and installed gears, gent at LineX updated ECM first time but I’ve modified ECM several times myself.

Jim

 

[mx5red]

LOL, having 4:88 installed in my JT Rubicon today.

Make sure they re-calibrate the air sensor in that electronic diff…

 

[JeepCares]

Update June 7th 2021. Called the dealership last night. No updates and was told this will most likely take a very long time to resolve. Still no word from @JeepCares

Thank you for all the feedback. Looking forward to getting some level of resolution.

Sorry for the delay here. When you have a moment, feel free to send us a private message with details on your concerns.

Kate
Jeep Cares

 

[FitfulGoat]

Make sure they re-calibrate the air sensor in that electronic diff…

And top off the LED blinker fluid as well while they are at it

 

[CerOf]

And top off the LED blinker fluid as well while they are at it

Blinker fluid is on back order.

 

[guarnibl]

I had Mopar 4:88's installed in my Rubicon by a local Jeep dealership. Before I left the parking lot the auto start stop threw a warning light and became inoperable. I called the dealership and they assumed it was the auxiliary battery and told me I would need to bring it back and let them have it for 4 hours to test the battery and if/when it was bad they could replace it under warranty.

Fast forward a month and I drop it off to receive a call letting me know they have programmed the 4:88's but every time they start it and pull it out of the shop the auto start stop issue pops back up. When they go back into the programming it has changed back to 4:10's. They let me know I can come pick up the truck and they will work with Jeep to get new code and call me back when they get it.

Two weeks later (last Monday) I take the truck back as they now say they need to regional Jeep guy here so they can connect the system up and work with Jeep as they cant figure out what is going on. I was in the area (today Friday)so I popped in the dealership to see if they had made in progress. Here is where it gets FUN!!!

I have now been informed that you can not put 4:88's in a Rubicon because the rear diff has some air sensor in it and now that they have done both the rear and and front end both axles need to be replaced along w/ the transfer case. They informed me this is only an issue with Rubicon and that if I had a sport or Mojave no big thing. At this point I have no truck, no idea what resolution looks like and scratching my head as to how the heck this is even possible.

Please dont shoot the messenger as I am only sharing what I have been told. Please do share if you have a Rubicon, had a dealership install 4:88's and if you are not having the same problem would really appreciate a PM with your dealership name so I can have mine call yours and compare notes.

All that said I really dont want to go back to 4:10's so need to start looking at other axles as a potential resolution. Thanks in advance for any guidance, positive input or good natured go buy a Ford smack talk as it is all appropriate about right now.

@JeepCares

This is completely false.

Also, FCA won't likely approve such a replacement anyway, lol. Next message from dealer -- you owe $20k for them to fix it.

 

[Russler]

For future reference or anyone else that may experience the same type of issue. My Jeep Cares case number for this is 79708336.

 

[Russler]

This is completely false.

Also, FCA won't likely approve such a replacement anyway, lol. Next message from dealer -- you owe $20k for them to fix it.

$20k for a muffler belt is a little steep . On a serious note, I dont think the dealership agrees w/ the Jeep representative in this case. They have worked with parts to try and identify above mentioned air sensor....nope, cant figure that one out. They have researched both Jeep and non Jeep resources and coming to the same conclusion as the rest of us. All that said I believe resolution lies squarely in Jeeps hands and guessing it will be a matter of time before I can share resolution.

In the interim I am driving a brand new Gladiator with auto.....I miss my manual

 

[guarnibl]

$20k for a muffler belt is a little steep seriously, I dont think the dealership agrees w/ the Jeep representative in this case. They have worked with parts to try and identify above mentioned air sensor....nope, cant figure that one out. They have researched both Jeep and non Jeep resources and coming to the same conclusion as the rest of us. All that said I believe resolution lies squarely in Jeeps hands and guessing it will be a matter of time before I can share resolution.

In the interim I am driving a brand new Gladiator with auto.....I miss my manual

Yeah I was just kidding -- more to point out to me that such a statement wouldn't be any more crazier than the first.

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